Officially, Fiat chairman Luca di Montezemolo, Italian car industry grandee for a quarter of a century, has announced his retirement “because he has completed the assignment given to him”.

Excuse me, however, if I choose to presume that there’s more to it than that - especially since Automotive News (usually well plugged into the Italian scene) reports well-placed sources as suggesting that a big part of Montezemolo’s motivation is that he doesn’t agree with the big plan planned by CEO Sergio Marchionne, to separate the Fiat automotive interests (currently responsible for more than 50 per cent of its earnings) from the rest of the group.

What strikes me as highly unusual is that Montezemolo has clearly lost a key boardroom battle, something which hasn’t happened in living memory, at least in public. Credited with reviving Ferrari after the death of the founder and building it into a powerful industrial enterprise, Montezemolo has had what amounts to dictatorial powers for many years.

Now his authority has been tested against that of Sergio Marchionne, and the younger man is clearly the winner. Montezemolo will stay on the Fiat board, and will continue to play in the Ferrari backyard as chairman, but his time at the top if Fiat has ended.

This afternoon we heard chapter and verse about Fiat Auto’s (and Chrysler’s) corporate and model strategy for the next five years. The decisive boardroom victory of Marchionne over Montezemolo means that if his new set-up succeeds - as a growing group of pundits, even Americans, suggest it will - only one man will be able to take the credit.

If it fails, only one man will take the blame.